Too many INFO log messages written out during AM to RM heartbeat. Based on default frequency of 1000ms (scheduler.heartbeat.interval-ms) either 2 or 4 INFO messages are written out per second:
LOG.info("Before Scheduling: " + getStat());
List<Container> allocatedContainers = getResources();
LOG.info("After Scheduling: " + getStat());
if (allocatedContainers.size() > 0)
These should probably be changed to DEBUG message to save the log growing too quickly.